Stabilization of glyceridic oils



2,699,395 Patented Jan. 11, 1955 2,699,395 STABILIZATION OF GLYCERIDICOILS Carl BrownyJersey. City,N. J., and Chester M. Gooding,= StatenIsland, N. Y., assignors to The Best Foods, Inc, New York, N. Y., acorporationof New Jersey NoDraWing. ApplicationOctober 24, 1950,

Serial N0.191,915

13 Clainisi (Cl-99 463) I Thislinventionrelates .to glyceridic oils andmore particularly to glyceridic: oils possessing'marked resistance todeteriorationl An object of thisinvention isto retard the deteriorationof glyceridic oils and more particularly hydrogenated and deodorizedglyceridic oils, such as hydrogenated and deodorized soya bean oil.

Another object of this invention is to retard for relatively prolongedperiodsthe development of rancidity of glyceridic oils.

A more particular object of this invention is to disperse uniformlythroughout a body of glyceridic oil effective amounts of Certaintricarboxylic acidswhich are capable of retarding the development ofrancidity in such glyceridic oils.

Certain tricarboxylic acids are effective for retarding the developmentof rancidity of glyceridic oils. However,flsome of these.tricarboxyliciacids, .such as citric acid, are only negligibly solublein glyceridic oils and i would be substantially it ineffectiveforpreventing flavor deterioration of suchoils if added directly Ito theoil, particularly if a large bodyiof oil were to be treated. Again, forsmall bodies of oil maintained at room temperature, the addition ofsuchtricarboxylic acids, when added directly, might effect some degreeof stabilization. If, however such ciils are required to be processedorused at e'levatedtemperatures and under adverse conditions; the limitedsolubility of suchtricarboxylic acids would not provide adequateconcentrations to effect a useful'degreeof stabilization. e

In accordance with this invention, tricarbox'ylic acids having sixcarbon atoms and no functional groups other than the hydroxylgroupa'ndthe carboxyl'group, are uniformly dispersed throughout a bodyof an edible glyceridic oil in concentrations sufficient to achievemaximum flavor stability under unfavorable conditions. For this purpose,a tricarboxylic acid having six carbon atoms is dissolved in any one ormore of the following estersof polyhydric alcohols: Mono-fatty acidesters of glycerol, jdi-fatty acid esters of glycerol, mono-fattyacidesters of propylene glycol, or the condensation products of any of theseesters with propylene oxide, the propylene moiety P1100510 exceedrfourin such polymers. The resulting solution. of thetricarboxylicacid inthe ester is then added to the edible glyceridic'oil, the tricarboxylicacid being uniformly distributed throughout the body of the oil by anysuitable means, such as agitation. The fatty. acids employed in thepreparation of the fatty esters of the polyhydric alcohol may be anyfatty acid, although preferably the fatty acid is a saturated orunsaturated fattyw.acidwhaving :from 12 to 18 carbon atoms, such aslauric, myristic, palmitic, oleic or stearic acids.

It is not understood how the practice of this invention results in aconcentration of tricarboxylic acid in a triglyceridic oil markedlyhigher than that which can be achieved by the usual methods. However,While this invention is not restricted to any particular theory, it isbelieved that the addition of the compositions described herein to atriglyceridic oil results in establishing a favorable condition, whereina very large surface of contact between the triglyceridic oil and theextremely finely dispersed tricarboxylic acid results from the rapiddilution of the compositions of this invention by the glyceridic oil atthe time of admixture.

Examples of the tricarboxylic acid which may be em ployed in accordancewith this invention are citric acid, aconitic acid, tricarballylic acidand iso-citric acd.

The tricarboxylic acid may be incorporated in the glyceridic oil byadding the solution of the tricarboxylic acid in the fatty acid ester ofthe polyhydric alcohol to the oil which is maintained in a liquid state.Any temperature at which the oil is completely liquid is satis factoryfor this purpose. The tricarboxylic acid 1s uniforrnly distributedthroughout. the body of the oil by any convenient means of agitation,such as stirring. The

means of agitation should be sufficiently rapid and thorough to insurethe uniform distribution of the .tricarboxylic acid throughout the bodyof the oil. A preferred method employs the use of a proportioning pumparranged to continuously inject the desired quantity of tricarboxylicacid into a stream of the oil to be treated as it is discharged from adeodorizer and while the oil being treated is still under vacuum. a

A more comprehensive understanding of this invention is obtained byreference to the following examples:

Example 1 0.25 part of the solution of the citric acid in the fatty acidesters of. glycerol is added to parts of hydrogenated and deodorizedsoya bean oil maintained at a temperature of about 60 C. The citric acidmay be uniforrnly distributed throughout the body of the oil bysubjecting it to mechanical stirring. Preferably, the solution of citricacid in the esters is injected into theoil stream continuously byemploying the proportioning pump heretofore described.

Example 2 Five parts of citric acid monohydrate U. S. P. are dissolvedin 100 parts of a mixture of about equal parts of monand di-fatty acidesters of glycerol which have been washed to freethe mixture ofglycerol. The fatty acids of the glycerol esters were obtained from cornsalad oil.

This solution of citric acid in the monoand di-fatty glycerides of cornsalad oil fatty acids is used to treat corn salad oil at the time ofcompletion of deodorization by means of the proportioning pumpheretofore described. The proportioning pump is adjusted so thatthecitric acid content of the resulting oil is about 0.005%.

Example 3 Pure propylene glycol monostearate is prepared by thecatalyzed condensation of propylene oxide with stearic acid;Seve'nty-fiveparts of propylene glycol monostearate are agitated withfifteen parts of powdered anhydrous seed and 40 parts of soya bean oilshydrogenated for making margarine. It may be incorporated in the oil byaddition, with subsequent agitation, or by injection in a stream of theoil at a temperature of about 60 C. in the manner heretofore described.

Example 4 Five parts of aconitic acid are dissolved at 80 C. in 100parts of the propylene oxide condensation product with the mono-fattyacid esters of glycerol employed in Example 1. The condensation productis produced by the reaction of one molecular proportion of themono-fatty esters of glycerol with four molecular proportions ofpropylene oxide.

0.2 part of the solution of the aconitic acid in the fatty acid ester isadded to 100 parts of a hydrogenated and deodorized soya salad oil anduniformly dispersed throughout the body of the oil by either of themethods heretofore described,

Example Example 6 Example 1 is repeated except that aconitic acid isemployed instead of citric acid.

Example 7 Example 1 is repeated except that tricarballylic acid isemployed instead of citric acid.

It is desirable that the amount of tricarboxylic acid dissolved in thefatty acid esters of the polyhydric alcohol be at a level of at least0.5 part, and preferably at least one part of tricarboxylicacid to 100parts of ester. It is also desirable that the amount of tricarboxylicacid incorporated in the edible glyceridic oil be within the range of0.002 to 0.1%, and preferably within the range of 0.01 to 0.05% of theglyceridic oil.

By the term glyceridic oil is meant any glyceridic fat in liquid orsolid form which may or may not be specifically processed to attaindesirable properties, such as plasticity or melting point.

The terms and expressions which we have employed are used as terms ofdescription and not of limitation, and we have no intention in the useof such terms and expressions of excluding any equivalents of thefeatures described or portions thereof, but recognize that variousmodifications are possible within the scope of the invention claimed.

What is claimed is:

1. A method of retarding the development of rancidity of an edibleglyceridic oil, said method comprising adding to said glyceridic oil analiphatic tricarboxylic acid dissolved in an ester of a polyhydricalcohol and substantially uniformly distributing said aliphatictricarboxylic acid through the body of said oil, said tricarboxylic acidhaving six carbon atoms and having no functional groups other than thehydroxyl group and the carboxyl group, and said ester being selectedfrom the class consisting of monofatty acid esters of glycerol,'di-fatty acid esters of glycerol, mono-fatty acid esters of propyleneglycol and the condensation products of any of said fatty acid esterswith not more than four molecular equivalents of propylene oxide.

2. A method of retarding the development of rancidity of an edibleglyceridic oil, said method comprising adding to said glyceridic oilcitric acid dissolved in a fatty acid ester of a polyhydric alcohol andsubstantially uniformly distributing said citric acid throughout thebody of said oil, said fatty acid ester being selected from the classconsisting of: mono-fatty acid esters of glycerol, di-fatty acid estersof glycerol, mono-fatty acid esters of propylene glycol and thecondensation products of any of said fatty acid esters with not morethan four molecular equivalents of propylene oxide.

3. A method of retarding the development of rancidity of an edibleglyceridic oil, said method comprising adding to said glyceridic oilaconitic acid dissolved in a fatty acid ester of a polyhydric alcoholand substantially uniformly distributing said aconitic acid throughoutthe body of said oil, said fatty acid ester being selected from theclass consisting of: mono-fatty acid esters of glycerol, difatty acidesters of glycerol, mono-fatty acid esters of propylene glycol and thecondensation products of any of said fatty acid esters with not morethan four molecular equivalents of propylene oxide.

4. A method of retarding the development of rancidity of an edibleglyceridic oil, said method comprising adding to said glyceridic oiltricarballylic acid dissolved in a fatty acid ester of a polyhydricalcohol and substantially uniformly distributing said tricarballylicacid throughout the body of said oil, said fatty acid ester beingselected from the class consisting of: mono-fatty acid esters ofglycerol, di-fatty acid esters of glycerol, mono-fatty acid esters ofpropylene glycol and the condensation products of any of said fatty acidesters with not more than four molecular equivalents of propylene oxide.

A method of retarding the development of rancidity of an edibleglyceridic oil, said method comprising adding to said glyceridic oilcitric acid dissolved in a monofatty acid ester of glycerol. andsubstantially uniformly diftributing the citric acid throughout the bodyof said or 6. A method of retarding the development of rancidity of anedible glyceridic oil, said method comprising adding to said glyceridicoil citric acid dissolved in a di-fatty acid ester of glycerol andsubstantially uniformly distributing the citric acid throughout the bodyof 'said oil.

7. A method of retarding the development of rancidity of an edibleglyceridic oil, said method comprising adding to said glyceridic oilcitric acid dissolved in a mono-fatty acid ester of propylene glycol andsubstantially uniformly diftributing the citric acid throughout the bodyof said 01 8. A method of retarding the development of rancidity of anedible glyceridic oil, said method comprising adding to said glyceridicoil aconitic acid dissolved in a monofatty acid ester of glycerol andsubstantially uniformly distributing the aconitic acid throughout thebody of said oil.

9. A method of retarding the development of rancidity of an edibleglyceridic oil, said method comprising adding to said glyceridic oiltricarballylic acid dissolved in a mono-fatty acid ester of glycerol andsubstantially uniformly distributing the tricarballylic acid throughoutthe body of said oil.

10. A method as defined in claim 1 in which the edible glyceridic oilcomprises hydrogenated deodorized soya bean oil.

11. A method as defined in claim 2 in which the edible glyceridic oilcomprises hydrogenated deodorized soya bean oil. 1

12. A method as defined in claim 3 in which the edible glyceridic oilcomprises hydrogenated deodorized soya bean oil.

13. A method as defined in claim 4 in which the edible glyceridic oilcomprises hydrogenated deodorized soya can 01 References Cited in thefile of this patent UNITED STATES PATENTS Rogers May 12, 1931 Brown June5, 1945 OTHER REFERENCES

1. A METHOD OF RETARDING THE DEVELOPMENT OF RANCIDITY OF AN EDIBLEGLYCERIDIC OIL, SAID METHOD COMPRISING ADDING TO SAID GLYCERIDIC OIL ANALIPHATIC TRICARBOXYLIC ACID DISSOLVED IN AN ESTER OF A POLYHYDRICALCOHOL AND SUBSTANTIALLY UNIFORMLY DISTRIBUTING SAID ALIPHATICTRICARBOXYLIC ACID THROUGH THE BODY OF SAID OIL, SAID TRICARBOXYLIC ACIDHAVING SIX CARBON ATOMS AND HAVING NO FUNCTIONAL GROUPS OTHER THAN THEHYDROXYL GROUP AND THE CARBOXYL GROUP, AND SAID ESTER BEING SELECTEDFROM THE CLASS CONSISTING OF MONOMONO-FATTY ACID ESTERS OF PROPYLENEGLYCOL AND THE CONDENSATION PRODUCTS OF ANY OF SAID FATTY ACID ESTERSWITH NOT MORE THAN FOUR MOLECULAR EQUIVALENTS OF PROPYLENE OXIDE.